[Si:1]([O:8][CH2:9][C@H:10]1[O:14][C:13](=[O:15])[CH:12]=[CH:11]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].C(C1C=CC=CC=1)(=O)C1C=CC=CC=1.[C:30]([O:33][CH2:34][CH3:35])(=[O:32])C.C(Cl)(Cl)Cl>O1CCOC1>[Si:1]([O:8][CH2:9][C@H:10]1[O:14][C:13](=[O:15])[CH2:12][C@@H:11]1[CH:30]1[O:33][CH2:34][CH2:35][O:32]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]A solution containing 228 mg (0.998 mmol) compound (2a) and 18.0 mg (0.998 mmol) benzophenone in 200 mL [1,3]-dioxolane was irradiated at 20° C. for 5 hours according to the general procedure. Column chromatography (silica gel 35 g, ethyl acetate in hexanes 30%) gave compound (3a) (285 mg, 94%) as a colorless solid, Rf=0.35, [α]25D 18.3°, c 1.3, CHCl3, IR (neat) 2953, 2857, 1778, 1125 cm−1; 1H-NMR (300 MHz, CDCl3) δ: 0.05 (s, 6H), 0.87 (s, 9H), 2.45 (dd, 1H, J=4.2 Hz, J=17.7 Hz), 2.68 (d, 1H, J=17.7 Hz), 2.72-2.79 (m, 1H), 3.65 (dd, 1H, J=2.7 Hz, J=11.4 Hz), 3.86-3.91 (m, 3H), 3.97-4.01 (m, 2H), 4.50 (mc, 1H), 4.88 (d, 1H, J=3.6 Hz). 13C-NMR (75.4 MHz, CDCl3, Dept) δ: 5.52 (+), 18.18 (quat), 25.77 (+), 30.12 (−), 39.67 (+), 64.71 (−), 65.36 (−), 65.47 (−), 80.24 (+), 103.94 (+), 176.55 (quat). C14H26O5Si; Exact Mass: 302.15; Mol. Wt.: 302.44; C, 55.60, H, 8.67, O, 26.45, Si, 9.29.
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